Question: Nadia is 64 years old and Stephanie is 4 years old. How many years will it take until Nadia is only 5 times as old as Stephanie?
Explanation: We can use the given information to write down an equation about how many years it will take. Let $y$ be the number of years that it will take. In $y$ years, Nadia will be $64 + y$ years old and Stephanie will be $4 + y$ years old. At that time, Nadia will be 5 times as old as Stephanie. Writing this information as an equation, we get: $64 + y = 5 (4 + y)$ Simplifying the right side of this equation, we get: $64 + y = 20 + 5 y$ Solving for $y$ , we get: $4 y = 44$ $y = 11$.